Novel Propylene Polymer Compositions

ABSTRACT

The invention relates to propylene polymer compositions comprising 50-70 wt % of a propylene homo- or copolymer, 5-20 wt % of a first elastomeric ethylene-propylene copolymer, 5-25 wt % of a second elastomeric ethylene-propylene copolymer and 5-30 wt % of an ethylene polymer. The propylene polymer compositions are suitable for moulding and they have low haze and a good impact strength/stiffness balance with good impact strengths at low temperatures.

FIELD OF INVENTION

The present invention relates to propylene polymer compositions whichare suitable for moulding, especially injection moulding. Moreparticularly the propylene polymer compositions can be used forpackaging applications, especially for deep freeze packagingapplications because they have excellent impact strength/stiffnessbalance at low temperatures, sufficient flowability and good opticalproperties.

DESCRIPTION OF PRIOR ART

Transparent polypropylene compositions with superior toughness at lowtemperatures have become an important market trend in recent years. Onetype of targeted products is rather stiff with flexural moduli wellabove 800 MPa. Materials with good stiffness are required becausestructural integrity is necessary for the intended products in themoulding segment, e.g. for boxes, crates, thin wall packaging, etc.

Types of propylene polymers having the required transparency are forexample propylene random copolymers with ethylene as comonomer. However,their impact resistance below 0° C. is insufficient and stiffness isbelow the required level.

There are also propylene polymers known, which have the required impactresistance at low temperatures. These polymers are heterophasicpropylene copolymers, having a rubber phase (usually about 20-30 wt %rubber phase with 40-60 wt % propylene) dispersed in a continuous matrixphase. For a good low temperature impact resistance, the molecularweight of the rubber phase is higher than the molecular weight of thematrix phase. These heterophasic propylene copolymers are however veryopaque. If the molecular weight of the polymer in the dispersed phase islower than that of the matrix phase, transparency is increased andimpact resistance is decreased. A lower total MFR of the compositionresults in an increased impact strength, however, the processability ofthe polymer composition which is required for the intended application(injection moulding) decreases.

OBJECT OF THE INVENTION

It is therefore the object of the invention, to provide a polypropylenecomposition for moulding, which has low haze and which simultaneouslyshows a good impact strength/stiffness balance with good impactstrengths at low temperatures.

The above object was achieved with a polypropylene composition having anMFR (230° C./2.16 kg)≧8 g/10 min comprising

A) 50-70 wt % of a propylene polymer comprising a propylene homopolymerand/or a propylene copolymer with up to 5 wt % ethylene and/or one ormore C₄-C₈ α-olefins and having an intrinsic viscosity IV_(A) 1.00-2.20dl/g

B) 5-20 wt % of a first elastomeric ethylene-propylene copolymer havingan intrinsic viscosity IV_(B) 1.65-2.50 dl/g and an ethylene content of20-40 wt %, preferably of 20-30 wt %, with IV_(B)>IV_(A),

C) 5-25 wt % of a second elastomeric ethylene-propylene copolymer havingan intrinsic viscosity IV_(C) of 0.90-1.60 dl/g and an ethylene contentof 45-85 wt %, preferably of 50-75 wt %,

D) 5-30 wt % of an ethylene polymer having an ethylene content of atleast 80 mol % and having a melt index MI (190° C., 2.16 kg) of at least5 g/10 min and a density of 905-925 kg/m³.

The propylene polymer A used for the propylene polymer compositionaccording to the invention is either a propylene homopolymer or apropylene copolymer or mixtures thereof. When the propylene polymercomprises a propylene copolymer, the copolymer contains up to 5 wt % ofethylene and/or one or more C₄-C₈ α-olefins, preferably up to 2 mol % ofcomonomers. Among possible comonomers, ethylene and 1-butene arepreferred.

It is further important, that the propylene polymer A has an intrinsicviscosity IV_(A) 1.00-2.20 dl/g in order to guarantee a high flowabilityof the end-product.

It is also essential for the present invention, that a first elastomericethylene-propylene copolymer B having a low ethylene content of 20-40 wt% and a high intrinsic viscosity IV_(B) of 1.65-2.50 dl/g and a secondelastomeric ethylene-propylene copolymer C having a high ethylenecontent of 45-85 wt % and a low intrinsic viscosity of 0.90-1.60 dl/gare present.

It was found, that it is beneficial for the impact strength, when themolecular weight of the elastomeric ethylene-propylene copolymer B withthe low ethylene content is higher than the molecular weight of thepropylene polymer A. Therefore, it is required that IV_(B)>IV_(A).

A further essential component of the present invention is an ethylenepolymer having an ethylene content of at least 80 mol %. For achievinggood optical properties it is important for the ethylene polymer to havea melt index MI (190° C., 2.16 kg) of at least 5 g/10 min. Lower meltindices do not result in a composition having low haze. When the meltindex of the ethylene polymer is too high, especially when it is >100g/10 min the mechanical properties of the compositions, in particulartoughness, are not sufficient.

Preferred ethylene polymers are LDPE and LLDPE.

The compositions of the present invention preferably have an MFR (230°C., 2.16 kg) of from 8 to 60 g/10 min.

According to an advantageous embodiment, the first elastomericethylene-propylene copolymer has an intrinsic viscosity IV_(B) of1.80-2.25 dl/g.

It is further preferred, that the second elastomeric ethylene-propylenecopolymer has an intrinsic viscosity IV_(C) of 0.90-1.50 dl/g.

For the polypropylene compositions according to the invention it ispreferred, that the difference between the intrinsic viscosities of thefirst and second elastomeric ethylene-propylene copolymers IV_(B)−IV_(C)is ≧0.2 dl/g. It is still more preferred, that IV_(B)−IV_(C) is ≧0.4dl/g.

For the polypropylene compositions of the present invention it ispreferred that they contain, based on the total weight of components Ato D, from 0.01-2 wt % of (X-nucleating agents.

The addition of α-nucleating agents (of which some may also act asclarifiers) to propylene polymers increases their stiffness (andtransparency). α-nucleating agents and clarifiers are therefore addedfor a high absolute level of stiffness and transparency.

Suitable α-nucleating agents include talc having a particle size of0.01-1.0 μm, sodium benzoate,sodium-2,2′-methylene-bis(4,6-di-t-butylphenyl)phosphate,sodium-bis(4-t-butylphenyl)phosphate,1,3,2,4-di(3′,4′-dimethylbenzylidene)sorbitol and “ADK STAB NA21 E”available from Asahi Denka Kogyo (Japan). If talc is used as nucleatingagent, it is usually present in an amount of 0.01-1.0 wt %, which is aneffective amount for α-nucleating, but which is not a sufficient amountwhere talc would already act as filler. A preferred nucleating agent is1,3,2,4-di(3′,4′-dimethylbenzylidene)sorbitol, which is available as“MILLAD 3988” from Milliken.

According to an advantageous embodiment the ratio (B+C)/D of the amountsof elastomeric copolymers (B+C) to the amount of ethylene polymer D isfrom 0.3 to 2.5.

It has been found, that outside of this ratio haze and impact strengthare unsatisfactory.

The polypropylene compositions of the present invention are preferablyproduced by mixing

A) 50-70 wt % of a propylene polymer comprising a propylene homopolymerand/or a propylene copolymer with up to 5 wt % ethylene and/or one ormore C₄-C₈ α-olefins and having an intrinsic viscosity IV_(A) 1.00-2.20dl/g,

B) 5-20 wt % of a first elastomeric ethylene-propylene copolymer havingan intrinsic viscosity IV_(B) 1.65-2.50 dl/g and an ethylene content of20-40 wt %, with IV_(B)>IV_(A),

C) 5-25 wt % of a second elastomeric ethylene-propylene copolymer havingan intrinsic viscosity IV_(C) of 0.90-1.60 dl/g and an ethylene contentof 45-85 wt %,

D) 5-30 wt % of an ethylene polymer having an ethylene content of atleast 80 mol % and having a melt index MI (190° C., 2.16 kg) of at least10 g/10 min and a density of 905-925 kg/m³, melting and homogenising andcooling and pelletising the mixture.

The propylene polymer compositions of the present invention arepreferably produced by combining the propylene polymer A in the form ofpowder or granules, the elastomeric copolymers B and C and the ethylenepolymer D and any additives and/or nucleating agents in a melt mixingdevice.

Melt mixing devices suited for this process are discontinuous andcontinuous kneaders, twin screw extruders and single screw extruderswith special mixing sections and co-kneaders. The residence time must bechosen such that a sufficiently high degree of homogenisation isachieved.

Due to their advantageous property profile, the polymer compositions ofthe present invention are especially suited for injection mouldingapplications. The polymer compositions of the present invention areparticularly suited for packaging applications, including thin wallpackaging, for low temperatures.

Production of Propylene Polymer A

The propylene polymer A may be produced by single- or multistage processpolymerisation of propylene or propylene and ethylene such as bulkpolymerisation, gas phase polymerisation, slurry polymerisation,solution polymerisation or combinations thereof using conventionalcatalysts. A homo- or copolymer can be made either in loop reactors orin a combination of loop and gas phase reactor. Those processes are wellknown to one skilled in the art.

A suitable catalyst for the polymerisation of the propylene polymer isany stereospecific catalyst for propylene polymerisation which iscapable of polymerising and copolymerising propylene and comonomers at atemperature of 40 to 110° C. and at a pressure from 10 to 100 bar.Ziegler Natta catalysts as well as metallocene catalysts are suitablecatalysts.

One skilled in the art is aware of the various possibilities to producepropylene homo- and copolymers and will simply find out a suitableprocedure to produce suitable polymers which are used in the presentinvention.

Production of Elastomeric Copolymers B and C

An ethylene propylene elastomeric copolymer may be produced by knownpolymerisation processes such as solution, suspension and gas-phasepolymerisation using conventional catalysts. Ziegler Natta catalysts aswell as metallocene catalysts are suitable catalysts.

A widely used process is the solution polymerisation. Ethylene,propylene and catalyst systems are polymerised in an excess ofhydrocarbon solvent. Stabilisers and oils, if used, are added directlyafter polymerisation. The solvent and unreacted monomers are thenflashed off with hot water or steam, or with mechanicaldevolatilisation. The polymer, which is in crumb form, is dried withdewatering in screens, mechanical presses or drying ovens. The crumb isformed into wrapped bales or extruded into pellets.

The suspension polymerisation process is a modification of bulkpolymerisation. The monomers and catalyst system are injected into thereactor filled with propylene. The polymerisation takes placeimmediately, forming crumbs of polymer that are not soluble in thepropylene. Flashing off the propylene and comonomer completes thepolymerisation process.

The gas-phase polymerisation technology consists of one or more verticalfluidised beds. Monomers and nitrogen in gas form along with catalystare fed to the reactor and solid product is removed periodically. Heatof reaction is removed through the use of the circulating gas that alsoserves to fluidise the polymer bed. Solvents are not used, therebyeliminating the need for solvent stripping, washing and drying.

The production of ethylene propylene elastomeric copolymers is alsodescribed in detail in e.g. U.S. Pat. No. 3,300,459, U.S. Pat. No.5,919,877, EP 0 060 090 A1 and in a company publication by EniChem“DUTRAL, Ethylene-Propylene Elastomers”, pages 1-4 (1991).

Alternatively, elastomeric ethylene-propylene copolymers, which arecommercially available and which fulfil the indicated requirements, canbe used.

Alternatively, polymers A, B and C may be produced in a series ofreactors, e.g. starting with the production of polymer A in a loopreactor, transferring the product into a first gas phase reactor, wherecopolymer B is polymerised and finally transferring the product of thefirst two reactors into a second gas phase reactor, where copolymer C ispolymerised.

Production of Ethylene Polymers D

It is preferred to use ethylene polymers which are commerciallyavailable, e.g. MA9230, CA9150, MA8200 from Borealis A/S. Alternatively,suitable ethylene polymers may be produced according to the followingdescriptions.

Low density polyethylene may be produced by free-radical-initiatedpolymerization using free radical initiators such as peroxide or oxygenin high pressure processes. The polymerization is carried out in tubularor stirred autoclave reactors at a temperature of about 130 to 330° C.and at a pressure around 700 to 3000 bars.

Linear low density polyethylene is made by the copolymerisation ofethylene and α-olefins. It may be produced in low pressure processessuch as gas-phase process (for which the Unipol technology is a typicalexample), a solution-phase polymerisation process, a slurry process, orcombinations thereof like staged gas phase (Union Carbide), stagedslurry/gas phase (Borealis) or staged solution phase (Nova). A suitablecatalyst for the polymerisation of LLDPE is any stereospecific catalystwhich is capable of polymerising and copolymerising ethylene andcomononers. Ziegler-Natta as well as metallocene catalysts are suitablecatalysts. In the gas-phase process, reactor temperatures are usuallybelow 100° C. with pressures of about 20 bars. In the solution process,reactor temperatures are usually 170-250° C. with pressures of 40-140bars. In the solution-phase polymerisation process, reactor temperaturesare usually 70-110° C. with pressures of 30-50 bars.

Measurement Methods

MFR

The melt flow rates were measured with a load of 2.16 kg at 230° C. forpolypropylene and at 190° C. for polyethylene. The melt flow rate isthat quantity of polymer in grams which the test apparatus standardisedto ISO 1133 extrudes within 10 minutes at a temperature of 230° C. or190° C. respectively, under a load of 2.16 kg.

The expressions “melt flow rate”, “MFR” and “melt index MI” are in thisdocument used synonymously for the respective property of propylenepolymers and ethylene polymers.

Comonomer contents were measured with Fourier transform infraredspectroscopy (FTIR) calibrated with ¹³C-NMR.

Intrinsic Viscosity

Intrinsic Viscosity was measured according to DIN ISO 1628-1 (October1999) in Decalin at 135° C.

Puncture Test

Impact strength was determined under biaxial loading. Puncture testsaccording to IS06603/2 at −20° C. were performed using 60*60*2 mminjection moulded samples. Two parameters were determined: F_(max), themaximum of the load-deflection curve, and W_(tot), the total energyabsorbed by the sample (i.e. the area under the load-deflection curve).

Bending Test

Bending tests were performed according to ISO 178 using 80*10*4 mminjection moulded specimens as described in EN ISO 1873-2. Bendingmodulus, E-modulus, was determined according to ISO 178 at 2 mm/min inbetween strains of 0.05% to 0.25%.

Haze

Haze was determined according to ASTM D 1003-92 on injection mouldedtest plaques (60×60×2 mm).

EXAMPLES Preparation of Polymers A

The propylene polymers A used for the present invention were preparedaccording to the following procedure:

Homopolymers:

Raw Materials:

Hexane dried over molecular sieve (3/10A)

TEAL: 93% from Sigma-Aldrich

Donor: Dicyclopentyldimethoxysilane: ex Wacker Chemie (99%).

N₂: supplier AGA, quality 5.0; purification with catalyst BASF R0311,catalyst G132 (CuO/ZNO/C), molecular sieves (3/10A) and P₂O₅.

Propylene: polymerisation grade

Hydrogen: supplier AGA, quality 6.0

The catalyst ZN104 is commercially available from Basell.

Sandostab P-EPQ is commercially available from Clariant.

A 20 l autoclave reactor has been purified by mechanical cleaning,washing with hexane and heating under vacuum/N₂ cycles at 160° C. Aftertesting for leaks with 30 bar N₂ over night reactor has been vacuumedand filled with 5250 g propylene by weighing and 51.4 nl H₂ by pressuremonitoring from a 50 l steel cylinder.

80 mg of ZN104-catalyst are activated for 5 minutes with a mixture ofTriethylaluminium (TEAl; solution in hexane 1 mol/l) andDicyclopentyldimethoxysilane as donor (0.3 mol/l in hexane)—in a molarratio of 4 after a contact time of 5 min—and 10 ml hexane in a catalystfeeder. The molar ratio of TEAl and Ti of catalyst is 250. Afteractivation the catalyst is spilled with 250 g propylene into the stirredreactor with a temperature of 23° C. Stirring speed is hold at 250 rpm.After 6 min prepolymerisation at 23° C. temperature is increased to 70°C. in about 14 min. After holding that temperature for 1 hourpolymerisation is stopped by flashing propylene and cooling to roomtemperature.

After spilling the reactor with N₂ the homopolymer powder is transferredto a steel container and stabilized with 0.1 wt % of Sandostab P-EPQ and0.2 wt % of Ionol in acetone and dried over night in a hood andadditionally for 2 hours at 50° C. under vacuum.

The amount of polymer powder (A2) was 1864 g and the MFR (230° C., 2.16kg) was 44 g/10 min.

Random Copolymers

Raw Materials:

Hexane dried over molecular sieve (3/10A)

TEAL: 93% from Sigma-Aldrich

Donor: Dicyclopentyldimethoxysilane: ex Wacker Chemie (99%).

N₂: supplier AGA, quality 5.0; purification with catalyst BASF R0311,catalyst G132 (CuO/ZNO/C), molecular sieves (3/10A) and P₂O₅.

Ethylene, Propylene: polymerisation grade

Hydrogen: supplier AGA, quality 6.0

The catalyst ZN101 is commercially available from Basell.

Sandostab P-EPQ is commercially available from Clariant.

A 20 l autoclave reactor has been purified by mechanical cleaning,washing with hexane and heating under vacuum/N₂ cycles at 160° C. Aftertesting for leaks with 30 bar N₂ over night reactor has been vacuumedand filled with 4250 g propylene by weighing.

23.9 mg of ZN101-catalyst are activated for 5 minutes with a mixture ofTriethylaluminium (TEAl; solution in hexane 1 mol/l) andDicyclopentyldimethoxysilane as donor (0.3 mol/l in hexane)—in a molarratio of 20 after a contact time of 5 min—and 10 ml hexane in a catalystfeeder. The molar ratio of TEAl and Ti of catalyst is 100. Afteractivation the catalyst is spilled with 250 g propylene into the stirredreactor. Stirring speed is hold at 215 rpm. After 15 minprepolymerisation at 13° C. 30 nl H₂ have been dosed into the reactorand constant ethylene dosing has been started to achieve the targetethylene content in the product. Stirring speed is increase to 250 rpmand temperature to 70° C. (achieved after 16 min). After holding theseconditions for 124 min (starting from dosing of H₂), polymerisation isstopped by flashing and cooling to room temperature.

After spilling the reactor with N₂ the random copolymer is transferredto a steel container and stabilized with 0.1 wt % of Sandostab P-EPQ and0.2 wt % of Ionol in acetone and dried over night in a hood andadditionally for 2 hours at 50° C. under vacuum.

The amount of polymer powder (A1) was 1520 g, ethylene content 1.2 wt %and the MFR (230° C., 2.16 kg) was 16 g/10 min.

The following polymers A were prepared: according to the aboveprocedures: polymer MFR C2 IV No. [g/10 min] [wt %] [dl/g] A1 16 1.21.48 A2 44 0 1.19

Preparation of Elastomeric Copolymers B and C

The elastomeric copolymers of the present invention were preparedaccording to the following procedure:

A 5 l-reactor (autoclave) filled with about 0.2 barg propylene(polymerisation grade) is pressured up with 3.0 barg H₂. Then 300 g ofpropylene are added.

5 mg of a ZN104 catalyst is contacted with 0.3 ml white oil for about 16hours and then activated for 5 minutes with a mixture ofTriethylaluminium (TEAl; solution in hexane 1 mol/l) andDicyclopentyldimethoxysilane as donor (0.3 mol/l in hexane)—in a molarratio of 76 using a contact time of 5 min. The molar ratio of TEAl andTi of catalyst was 380 and TEAl concentration in TEAl/donor mixture 12.6mg/ml hexane. After activation the catalyst is transferred to thereactor by spilling in with 500 g propylene. After 12 minpre-polymerisation at 30° C. 90 g of ethylene is added to the reactorand the temperature is increased to 55° C. During heating up additionalethylene dosing is started to achieve the pressure of 34.2 barg at 55°C. Total pressure is hold constantly via continuously dosing of ethyleneduring polymerisation. 30 min after end of prepolymerisation thereaction is stopped by flashing of monomers and cooling.

The amount of polymer powder was 102 g.

The polymer is stabilized with 0.1 wt % of Sandostab P-EPQ and 0.2 wt %of Ionol in acetone and dried over night in a hood and additionally for2 hours at 50° C. under vacuum.

The resulting rubber copolymer (B3) has an intrinsic viscosity of 2.11dl/g and an ethylene content of 49.8 wt %.

The following elastomeric ethylene-propylene copolymers were preparedaccording to the above procedure, except that H₂ and ethylene amountswere varied to achieve different intrinsic viscosities and comonomerconcentrations. polymer i.V. C2 No. [dl/g] [wt %] B1 2.00 22.8 B2 2.0125.9 B3 2.11 49.8 B4 2.17 29.5 B5 1.51 25.2 C1 1.05 67.4 C2 1.58 54.6 C31.03 70.5 C4 1.19 51.9

Ethylene Polymers D

The ethylene polymers D which are used for the present invention areselected among commercially available homo- and copolymers.

The following ethylene homo- and copolymers were used in the examples:Melt Index poly- commercial comonomer (190° C., mer grade content 2.16kg) density No. designation comonomer [wt %] [g/10 min] [g/cm³] D1MA9230 — — 22.0 0.923 D2 CA9150 — — 15.0 0.915 D3 MA8200 — — 7.0 0.920D4 FB4230 1-butene 6.5 0.4 0.923

The ethylene polymers MA9230, CA9150, MA8200 and FB4230 are commerciallyavailable from Borealis A/S.

For the examples (E1 to E8, CE1 to CE13), the appropriate amounts ofpropylene polymers A1 and A2, elastomeric ethylene-propylene copolymersB1 to B5 and C1 to C4, ethylene polymers D1 to D4, conventionaladditives (0.05 wt % Hydrotalcite (DHT-4A), 0.1 wt % Irgafos 168, 0.1 wt% Irganox 1010, 0.05 wt % Ca-stearate, in each case based on the sum ofthe weights of components A to D) and nucleant (0.2 wt % Millad 3988,based on the sum of the weights of components A to D) were mixed in anintensive mixer (Henschel mixer) for 25 seconds. The compositions werethen compounded in a twin screw extruder at a temperature of 250° C. Thestrands were quenched in cold water and pelletised.

The compositions (E2, CE4) were subjected to peroxidic degradation(visbreaking) with Altrix 3021. The MFR was increased up to about 30g/10 min.

The amounts of each component and the results of the measurements areshown in Tables 1 and 2. TABLE 1 component component component componentA B C D amount amount amount amount MFR type [pbw] type [pbw] type [pbw]type [pbw] [g/10 min] visbroken CE1 A1 76.5 B1 10.0 C1 13.5 — — 12.1 noInfluence of presence of E1 A1 68.8 B1 9.0 C1 12.2 D2 10.0 12.7 nocomponent D and of E2 A1 68.8 B1 9.0 C1 12.2 D2 10.0 33.8 yesvisbreaking CE2 A1 75.5 — — C2 24.5 — — 12.3 no Influence of presence ofCE3 A1 68.0 — — C2 22.0 D2 10.0 12.0 no component B and of CE4 A1 68.0 —— C2 22.0 D2 10.0 30.7 yes visbreaking CE5 A2 77.2 B2 8.5 C3 14.3 — —26.6 no Influence of presence of E3 A2 65.7 B2 7.2 C3 12.1 D2 15.0 24.0no component D with different CE6 A2 79.0 B5 21.0 — — — — 35.3 nocomponents B and C CE7 A2 67.1 B5 17.9 — — D2 15.0 34.5 no CE8 A2 78.5B3 7.9 C4 13.6 — — 31.5 no CE9 A2 66.7 B3 6.7 C4 11.6 D2 15.0 29.4 noCE10 A2 75.6 B4 4.7 C4 4.7 D2 15.0 31.9 no Influence of total amount ofCE11 A2 71.4 B4 6.8 C4 6.8 D2 15.0 29.1 no components B and C E4 A2 67.2B4 8.9 C4 8.9 D2 15.0 26.7 no CE11 A2 71.4 B4 6.8 C4 6.8 D2 15.0 29.1 noInfluence of amount of CE12 A2 67.4 B4 6.3 C4 6.3 D2 20.0 28.9 nocomponent D E5 A2 63.4 B4 5.8 C4 5.8 D2 25.0 30.4 no E6 A2 59.9 B2 9.4C3 15.7 D1 15.0 21.8 no Influence of type of E7 A2 59.9 B2 9.4 C3 15.7D2 15.0 20.6 no component D E8 A2 59.9 B2 9.4 C3 15.7 D3 15.0 19.1 noCE13 A2 59.9 B2 9.4 C3 15.7 D4 15.0 15.9 no E3 A2 65.7 B2 7.2 C3 12.1 D215.0 24.0 no Influence of ratio (B + C)/D CE14 A2 73.3 B2 8.1 C3 13.6 D2 5.0 25.0 no

TABLE 2 MFR Haze Fmax Wtot E-Modulus [g/10 min] [%] [N] [J] [MPa] CE112.1 88.2 1856 6.8 1128 Influence of presence of E1 12.7 59.4 2125 24.4955 component D and of visbreaking E2 33.8 75.7 2100 22.9 922 CE2 12.395.5 2591 15.9 1112 Influence of presence of CE3 12.0 84.8 2710 27.6 983component B and of visbreaking CE4 30.7 95.6 2643 25.6 880 CE5 26.6 95.01820 7.1 1495 Influence of presence of E3 24.0 71.6 2631 21.3 1238component D with different CE6 35.3 91.9 254 0.2 1390 components B and CCE7 34.5 61.8 388 0.4 1120 CE8 31.5 98.6 2297 10.2 1502 CE9 29.4 84.32656 20.7 1250 CE10 31.9 52.7 276 0.2 1269 Influence of total amount ofCE11 29.1 61.4 524 0.6 1179 components B and C E4 26.7 68.7 2695 20.61096 CE11 29.1 61.4 524 0.6 1179 Influence of amount of CE12 28.9 60.5541 0.7 1242 component D E5 30.4 53.3 2710 19.1 1066 E6 21.8 74.3 252728.9 1029 Influence of type of E7 20.6 76.3 2510 28.1 1027 component DE8 19.1 78.7 2524 28.1 1033 CE13 15.9 93.1 2527 27.1 1018 E3 24.0 71.62631 21.3 1238 Influence of ratio (B + C)/D CE14 25.0 91.0 1850 7.5 1435

1. A polypropylene composition for moulding having an MFR (230° C./2.16kg)≧8 g/10 min comprising A) 50-70 wt % of a propylene polymercomprising a propylene homopolymer and/or a propylene copolymer with upto 5 wt % ethylene and/or one or more C₄-C₈ α-olefins and having anintrinsic viscosity IV_(A) 1.00-2.20 dl/g, B) 5-20 wt % of a firstelastomeric ethylene-propylene copolymer having an intrinsic viscosityIV_(B) 1.65-2.50 dl/g and an ethylene content of 20-40 wt %, withIV_(B)>IV_(A), C) 5-25 wt % of a second elastomeric ethylene-propylenecopolymer having an intrinsic viscosity IV_(C) of 0.90-1.60 dl/g and anethylene content of 45-85 wt %, D) 5-30 wt % of an ethylene polymerhaving an ethylene content of at least 80 mol % and having a melt indexMI (190° C., 2.16 kg) of at least 5 g/10 min and a density of 905-925kg/m³.
 2. Polypropylene composition according to claim 1, wherein thefirst elastomeric ethylene-propylene copolymer has an intrinsicviscosity IV_(B) of 1.80-2.25 dl/g.
 3. Polypropylene compositionaccording to claim 1 or 2, wherein the second elastomericethylene-propylene copolymer has an intrinsic viscosity IV_(C) of0.90-1.50 dl/g.
 4. Polypropylene composition, according to claim 1 or 2,wherein IV_(B)−IV_(C)≧0.2 dl/g.
 5. Polypropylene composition accordingto claim 1 or 2, it contains further comprising, based on the totalweight of A to D, 0.01-2 wt % of α-nucleating agents.
 6. Polypropylenecomposition according to claim 1 or 2, wherein the ratio (B+C)/D of theamounts of elastomeric copolymers (B+C) to the amount of ethylenepolymer D is from 0.3:1 to 2.5:1.
 7. Process for producing apolypropylene composition of claim 1 or 2, comprising mixing A) 50-70 wt% of a propylene polymer comprising a propylene homopolymer and/or apropylene copolymer with up to 5 wt % ethylene and/or one or more C₄-C₈α-olefins and having an intrinsic viscosity IV_(A) 1.00-2.20 dl/g, B)5-20 wt % of a first elastomeric ethylene-propylene copolymer having anintrinsic viscosity IV_(B) 1.65-2.50 dl/g and an ethylene content of20-40 wt %, with IV_(B)>IV_(A), C) 5-25 wt % of a second elastomericethylene-propylene copolymer having an intrinsic viscosity IV_(C) of0.90-1.60 dl/g and an ethylene content of 45-85 wt %, D) 5-30 wt % of anethylene polymer having an ethylene content of at least 80 mol % andhaving a melt index MI (190° C., 2.16 kg) of at least 5 g/10 min and adensity of 905-925 kg/m³. melting and homogenising and cooling andpelletising the mixture.
 8. (canceled)
 9. Polypropylene composition,according to claim 1 or 2, wherein IV_(B)−IV_(C)≧0.4 dl/g.
 10. A methodof producing a shaped article, comprising injection molding acomposition of claim 1 or
 2. 11. A method of producing packaging,comprising injection molding a composition of claim 1 or
 2. 12. A methodof producing this wall packaging, comprising injection molding acomposition of claim 1 or
 2. 13. A shape article produced by the methodof claim
 9. 14. A shape article produced by the method of claim
 10. 15.A shape article produced by the method of claim 11.